Adam Johnson and James McClean played key roles in Wednesday's 1-0 victory over champions Manchester City, with the £10million England international contributing the winning goal and McClean providing a reminder of the form which propelled him into the Republic of Ireland squad for Euro 2012.

O'Neill said: "They can be a threat and this is the whole point. If we can get the ball out to Adam sometimes a wee bit more quickly than we do, then he can cause problems."

He added: "You would hope that would be the case. With James, we sat here a couple of months ago and we were talking about this second season syndrome, and I was hoping that it genuinely wouldn't be an insurmountable problem for him.

"I knew he would have difficulty early on, and that was shown by the number of times that full-backs went to close him so very quickly in matches.

"He is learning to cope with that now and I am hoping he will overcome it. But still, he will have games where he will be unable to do anything, simply because players have either marked him or things didn't happen for him. But overall, he is coming through."

Former Derry City midfielder McClean exploded on to the Premier League scene 12 months ago after being handed his debut as a substitute in O'Neill's first game in charge, and his elevation to the senior international stage soon followed.

Johnson, however, arrived on Wearside during the close-season with a far higher profile having made his name at Middlesbrough before earning a £7million switch to City, although it has taken him time to find his feet.

O'Neill said: "Essentially, he was on an excellent run at Middlesbrough, went to Manchester City and by his own admission, he would say he had more cameo roles than anything else, particularly in the last 18 months of his time there.

"To come in here and really be asked to do all the things that we think he's capable of doing, but to change our fortunes, one player changing everything, that was asking a lot. He had a wee bit of difficulty early on, but he is overcoming that and he's now starting to show in longer patches, anyway, the sort of form I think he is capable of."